Patent GB-1031891-A (GB)
Title: Improvements in and relating to bundles of glass fibres
IPC: C03B37/028
Filed: 1963-02-11
Abstract: An element formed of glass capillary tubes is made by assembling a glass which is capable of being etched away and tubes of inert glass in parallel relationship and then etching away the softer glass.  A tube 22 of resistant glass is carried by a clamp 301 forming part of a tube-lowering mechanism 341 and extends into a tube 24 of a non-resistant glass supported by a tube-lowering mechanism 34, the mechanisms 341, 34 being arranged to lower the tubes at the same or different speeds past a heater 28 to a drawing device.  The hollow fibre produced is cut into lengths, stacked, heated, and drawn to produce an assembly of capillary tubes of inert glass surrounded by non-resistant glass. The assembly is heated and compacted, the ends are coated with a wax, and the non-resistant glass is etched out except at the protected ends.  In modifications, the inner tube can be replaced by a rod of resistant glass, or a metal wire can be inserted in the inner tube so that the result is a number of electric conductive elements surrounded by insulating glass tubes.  The tubes are bound together at each end and mounted in an outer shell; if desired, the tubes can be arranged in groups and the groups twisted together. Some of the tubes may be closed at one end by a glass plug, the remainder being plugged at the opposite end.  The assembly can be used as a gas-diffusion device; by stopping off some of the tubes the device forms a printing plate, ink supplied to the upper surface of an assembly being fed by capillarity to the printing surface; by depositing a conducting material or an infra-red radiation transmitting material, e.g. arsenic sulphide, silver chloride, or germanium, in at least some of the tubes, an electrical image transfer device or a device for transmitting infra-red radiation can be produced.  Etching is preferably effected by nitric acid on a lanthanum silicate glass.ALSO:A gas-diffusion device formed of glass capillary tubes is made by assembling a glass which is capable of being etched away and tubes of inert glass in parallel relationship and then etching away the softer glass.  A tube 22 of resistant glass is carried by a clamp 30\sv forming part of a tube-lowering mechanism 34\sv and extends into a tube 24 of a non-resistant glass supported by a tube-lowering mechanism 34, the mechanisms 34\sv, 34 being arranged to lower the tubes at the same or different speeds past a heater 28 to a drawing device.  The hollow fibre produced is cut into lengths, stacked, heated, and drawn to produce an assembly of capillary tubes of inert glass surrounded by non-resistant glass. The assembly is heated and compacted, the ends are coated with a wax, and the non-resistant glass is etched out except at the protected ends. In modifications, the inner tube can be replaced by a rod of resistant glass, or a metal wire can be inserted in the inner tube so that the result is a number of electric conductive elements surrounded by insulating glass tubes.  The tubes are bound together at each end and mounted in an outer shell; if desired, the tubes can be arranged in groups and the groups twisted together.  Some of the tubes may be closed at one end by a glass plug, the remainder being plugged at the opposite end.  Etching is preferably effected by nitric acid on a lanthanum silicate glass.